Solid state imaging devices that use multiplication registers are known in the art (for example, those disclosed in Patent Documents 1 and 2). In such solid state imaging devices, an electric charge read out from an imaging region is transferred to a multiplication register via a horizontal shift register. The multiplication register typically includes an insulation layer formed on a semiconductor layer, and a transfer electrode formed on the insulation layer. In the multiplication register, in a state that a certain electrode (DC electrode) is fixed by applying a direct current to it, when an electric potential of a next-stage transfer electrode (multiplication electrode) is greatly increased, electron multiplication takes place when an electric charge is transferred between these electrodes. In such a solid state imaging device with an electron multiplying function, a method of injecting a certain amount of electric charge at a position just before the multiplication register and monitoring an output has been proposed with an object to monitor a multiplication factor (Patent Documents 1 and 2).